virtualization support x86 debugctl

Question

I'm playing around with the debug functions of the x86 processor and specifically trying to work with debugCtl functionality (http://support.amd.com/us/Processor_TechDocs/24593_APM_v2.pdf, page 353).

I tried to activate this feature by writing (in kernel mode on my vmplayer) 1 to the msr number 1d9 but when reading the value back I get a 0.

after a few hours of debugging my code I tried it on my physical computer and it worked. I searched the internet but I couldn't find any documentation about the subject of cpu feature support in virtualization products, and I cant figure out wheter I need to change the configuration to enable this feature or its not supported in vmware player, and whether it's supported in another in another virtualization product.

Answer 1

From what I understand VMWare player or Workstation does not support this. KVM does though but you would need to switch to a Linux box with QEMU.

I'm doing some stuff with that and when I change the MSR value (ECX = 0x1D9) it persists (rdmsr returns the proper value in EAX).

Like I said, I'm using QEMU on OpenSuse 12.2. I tried with VMWare 8 and wrmsr followed by rdmsr returned: EAX = 0x0